Cost comparison of continued anticoagulation with rivaroxaban versus placebo based on the 1-year EINSTEIN-Extension trial efficacy and safety results

Figures & data

Table 1. Base-case model inputs and ranges used in one-way sensitivity analysis.

	Base-case model input	Lower limit^c	Upper limit^c	References
Unit cost^a
Drug cost	$359.61^b	$287.68	$431.53	Red Book^18
Recurrent DVT	$60,000	$48,000	$72,000	Lin et al.^8; Lefebvre et al.^4
Recurrent PE	$60,000	$48,000	$72,000	Lin et al.^8; Lefebvre et al.^4
Major bleeding	$16,161	$12,929	$19,393	Ghate et al.^10
Clinically relevant non-major bleeding	$364	$291	$437	Ghate et al.^10
Rate difference/10,000 patients (rivaroxaban vs. placebo)
Recurrent DVT	–518	–828	–207	Wells et al.^17
Recurrent PE	–201	–505	103	Wells et al.^17
Major bleeding	68	2	134	Wells et al.^17
Clinically relevant non-major bleeding	583	241	926	Wells et al.^17

^aAdjusted to 2016 dollars.

^bBased on WAC Red Book for 20 mg 30 pill package.

^cLower and upper limits were defined as base-case input ±20% for unit costs and the 95% confidence intervals (CIs) of event rate differences.

Table 2. Drug costs per patient per year in rivaroxaban and placebo cohorts.

	Rivaroxaban [A]	Placebo [B]	Cost difference [A]–[B]
Daily dose^a, mg	20	–
Non-adherence rate^b	10%
Duration of treatment^c, months	7.57	–
Intended duration of treatment, %
6-months	59.8%	–
12-months	40.2%	–
Drug cost per package (WAC)^d, 2016 US$	$359.61	–
Number of pills per package	30	–
Total drug cost^e ($ per patient)	$2,723	$0	$2,723

^aDaily dose is based on the EINSTEIN-EXT study protocol.

^bA 10% non-adherence rate was assumed in this study to account for the fact that patients in clinical trials may not be fully adherent to the assigned treatment.

^cDuration of treatment was calculated as the weighted average of the intended duration of treatment with adjustment for the non-adherence rate in the population of the EINSTEIN-EXT study.

^dAll drug WAC prices are from the Red Book¹⁸.

^eTotal drug cost = duration of treatment × drug cost per package.

Table 3. Clinical event costs per patient per year in rivaroxaban and placebo cohorts.

Outcome	1-year KM rate^a (/10,000 patients)		Unit cost	Cost per patient per year
	Rivaroxaban	Placebo		Rivaroxaban	Placebo
Efficacy
Primary efficacy (PE or DVT)	298	963		$1,794	$6,102
Recurrent PE	154	355	$60,000^b	$924	$2,130
Recurrent DVT	145	662	$60,000^b	$870	$3,972
Safety
Major bleeding	68	0	$16,161	$110	$0
Clinically relevant non-major bleeding	766	183	$364	$28	$7
Total clinical event cost				$1,932	$6,109

^aWells et al.¹⁷.

^bDue to the lack of information in the literature on annual incremental cost of care associated with recurrent DVT and PE, respectively, the unit costs used for both recurrent DVT and PE events were based on the annual incremental all-cause healthcare cost associated with recurrent VTE (DVT or PE) estimated in two studies (Lefebvre et al.⁴ and Lin et al.⁸).

Figure 1. Total healthcare cost difference per patient per year between rivaroxaban- and placebo-treated patients.

Figure 2. Total healthcare cost difference per patient per year between rivaroxaban- and placebo-treated patients estimated in one-way sensitivity analysis. (1) Unit costs associated with drug, recurrent DVT, recurrent PE, major bleeding, or clinically relevant non-major bleeding varied by having its base unit cost decreased or increased by 20%. (2) The variation of a clinical event rate (i.e. recurrent DVT, recurrent PE, major bleeding, or clinically relevant non-major bleeding) was assessed based on the corresponding 95% confidence intervals (CIs) of rate differences between cohorts that were reported in the EINSTEIN-EXT study (Wells et al.¹⁷).

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